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At least 865 records · Page 48Linked to original sources
PubMed2002

Oropharyngeal swallowing variability.

OBJECTIVES/HYPOTHESIS: The pharyngeal phase of deglutition is considered to occur in a reflexive, preprogrammed fashion. Previous studies have determined a general sequence of events based on the mean timing of bolus transit and swallowing gestures. However, individual variability has not been studied. The purpose of the present study was to evaluate the amount of sequence variability that normally occurs during the oropharyngeal phase of deglutition. STUDY DESIGN: Prospective analysis of conservative subjects. METHODS: Dynamic swallow studies from 60 normal volunteers were evaluated, and event sequence variability was determined around two event sequences during swallowing of three bolus sizes. RESULTS: There was found to be substantial variability in event sequences for all events analyzed. Variability was greater during a smaller bolus swallow. CONCLUSIONS: The evaluation of variability within the study group of individuals reveals the complexity of the swallowing mechanism and underscores the importance of not relying on general guidelines in evaluating the coordination of swallowing gestures in a given individual with dysphagia complaints.

Adult↗
PubMed1993

Studies on fetal motor behaviour in normal and complicated pregnancies.

The possibility of studying fetal motor behaviour by ultrasound techniques has provoked research on its potential application for assessment of prenatal neurological conditions. The characteristics ('quality') of one particular movement pattern, the 'general movement', has been shown to be discriminative between uncomplicated pregnancy and major pathology of the developing central nervous system. Some recent studies have investigated whether the quality and/or the quantity of fetal movements correlated with other clinical variables during complicated pregnancies, and whether they provided prognostic information for the neurological outcome. Longitudinal research encompassing the pre- and postnatal periods was performed on uncomplicated pregnancies and on pregnancies complicated by intrauterine growth retardation, oligohydramnios (due to premature rupture of the amniotic membranes), or fetal breech position. Although the quantity of both fetal general movements and fetal breathing movements were found to be related to clinical variables of the fetal condition (such as heart rate variability, heart rate decelerations), clinical application seems limited due to large inter- and intra-individual variabilities. In contrast, the quality of fetal general movements appeared highly correlated with parameters of fetal clinical condition in individual cases and fulfilled several prerequisites for serving as a reliable diagnostic tool for prediction of the fetal condition and for assessment of the integrity of the central nervous system.

Female↗
PubMed2003

Reduction of the individual cancer risk by physical exercise.

The great variety of different types of human malignancies and the equally variable individual history of physical activity militate against finding any simple relationship between the risk of developing cancer and physical activity. Due to an obvious lack of prospective randomized trials, any evidence for a correlation is currently based on cohort and case control studies. Furthermore, the study results are sometimes inconsistent, and only for selected cancers, the available data are sufficient to draw any conclusions, resulting in a level of evidence of 2-3 (level of recommendation 'B'). Thus, a convincing risk reduction was found for colon cancer (40-50%) and estrogen-dependent malignancies such as breast (40-50%) and endometrial cancer (35-40%). Risk reduction is likely for some others, e. g. ovarian, lung or prostate cancer; but no definite conclusions can be drawn for hematological malignancies. Plausible explanations for reduction of the individual's cancer risk by increased physical activity are currently available for estrogen dependent cancers (breast, ovarian, endometrial) and colon cancers. The currently available data allow the recommendation of adopting a 'healthy life style' including physical activity for prevention of certain cancers.

Breast Neoplasms↗
PubMed1984

[Renal clearance technic for individualizing lithium dosage in routine hospital care].

Lithium has a narrow therapeutic index and exhibits a wide pharmacokinetic variability. Individual dosage regimen adjustment is necessary to warrant the efficacy and safety of long-term treatment. We propose the "renal clearance method" for rapid determination of the lithium carbonate daily dose for chronic therapy. After the first intake of drug by a manic-depressive patient, a four-hour trial is performed. It involves two blood samplings and two urine collections, in which lithium and creatine are assayed. Comparison of observed creatinine with a value predicted according to age, morphological characteristics, sex and serum creatinine of the patients allows the interpretation of conflicting results. The estimation of lithium and creatinine clearances of each patient is performed using a computerized or manual method which unfolds a decision procedure. The daily dosage (1.5 to 6 250 mg tablets in two or three daily intakes) is deduced from the according lithium renal clearance (0.4 to over 2 l/h) by means of a nomogram established in previous studies on about 50 patients. The clearance method has been investigated in routine hospital care on a 40 patients sample. The range of satisfactory lithium serum levels during patients monitoring was 0.6-0.9 mmol/l. Accurate dosage regimen forecasting is obtained in 92% of the patients. The percentage observed in a subset of 13 patients with the C24 method, which relies on a unique blood sample 24 hours after the first dose, was much lower (54%). The renal clearance method appears as a robust and reliable technique for individual lithium dosage regimen adjustment in routine care.

Adult↗
PubMed2005

Night-to-night variability in periodic leg movements in patients with restless legs syndrome.

BACKGROUND AND PURPOSE: Although a night-to-night variability in periodic leg movements (PLM) occurrence has been described in patients with primary PLM disorder and sleep apnea syndrome, no study has apparently considered the inter-night effect on PLM index during wakefulness and sleep in patients with Restless Legs Syndrome (RLS). Moreover, no study has examined the night-to-night variability in PLM index according to sleep stage and time of night. We therefore examined changes in PLM index during wakefulness and sleep during two consecutive nights in a group of untreated RLS patients. PATIENTS AND METHODS: Twenty-eight drug-free RLS patients, aged 53.4+/-2.3 yr, with a mean International Restless Legs Syndrome Study Group (IRLSSG) severity score of 20.2+/-1.6, were studied during two consecutive nights. PLM duration and interval, PLM index during wakefulness (PLMWI), during total sleep time (PLMSI), as well as during each sleep stage were measured. Analysis was also extended to examine PLM occurrence during sleep cycles. RESULTS: In the group of patients as a whole, the PLMW and PLMS index, duration and interval did not show significant difference between nights, these measures being consistently similar for both nights. Comparison of PLMS index between different sleep stages did not reveal inter-night differences. Nocturnal variation in PLM number, duration and interval for total recording time and sleep period revealed a progressive decline across the night for PLM index (P</=0.0001) but no interaction, the changes being similar in first and second nights. However, a large intra-individual variability was present with a correlation coefficient between nights of 0.60 for the PLMWI (P=0.001) and 0.54 (P=0.003) for the PLMSI. The individual inter-night changes in PLM index were independent of age, IRLSSG severity score, duration of the disease and changes in sleep parameters. CONCLUSIONS: This study shows that the index and the nocturnal pattern of PLM occurrence are highly reliable across nights in RLS patients, suggesting that a single-night study may be sufficiently sensitive to confirm diagnosis and associated sleep disturbances in these patients. However, an individual inter-night variability is present, independent of age, severity and duration of the disease, which should be considered in the clinical evaluation.

Adult↗
PubMed1975

Safe protein-calorie ratios in diets. The relative importance of protein and energy intake as causal factors in malnutrition.

There has been up to now a lack of agreement as to the way in which protein and energy requirements could be combined to give estimates of adequate dietary protein-energy ratios. In particular, the relevance of the simple ratio, average protein--average energy requirement as a basis for assessing diets, has been questioned on the grounds that it fails to take account of individual variability in needs for energy, and of the extent to which these may be independent of variability in protein requirements. The main problem is to evaluate the range over which individuals can adapt either energy intake to suit expenditure, or expenditure to suit intake, without detriment to health or growth. One solution adopted by Beaton and Swiss in a recent paper is to accept the range of observed variability of energy intakes in normal populations as a measure of this. An alterative is to make use of experimental evidence for the minimum energy intake for maintenance of body energy content. These two approaches are compared, and are shown to give quantitatively similar results. The method based on minimum maintenance requirements offers the further advantage that it allows an assessment of dietary situations in relation to the likelihood of occurrence of different forms of protein--energy malnutrition; those situations in which protein deficiency is a secondary consequence of low energy intake are differentiated from those in which the primary cause is an inadequate level of protein in the diet. The adequate "safe" level of protein-energy ratio in the diets of 2- to 3-year old children is close to 5% and since most varieties of cereal grains appear to provide utilizable protein levels of close to this amount, this lends further support to the view that primary protein deficiency is unlikely to be the main factor causing protein-energy malnutrition in communities for which cereals are the cheapest source of energy.

Breast Feeding↗
PubMedDate not supplied

[Variability and dynamics of micronuclei rate in participants of transatlantic march of the VIIth Ukranian Antarctic expedition].

The estimation of individual variability and group dynamics of micronuclei rate in buccal cells of participants of transatlantic march of the VIIth Ukrainian Antarctic expedition (Sevastopol--UAS "Akademik Vernadsky"--Sevastopol) was carried out. The general average rate of micronuclei was 2.20 per thousand. Individual values of micronuclei frequencies varied in wide limits. The maximum value of CV was 92.4% and the minimal one was 48.4%. Individual averages of micronuclei rates varied from 1.70 to 2.78 per thousand. Dependence of individual and group dynamics of micronuclei rates on environmental factors (temperature, atmospheric pressure and storm activity) was tested. No significant correlation of these parameters was found.

Adaptation, Physiological↗
PubMed1992

Micronuclei in bronchial biopsy specimens from heavy smokers: characterization of an intermediate marker of lung carcinogenesis.

Bronchial micronuclei, small fragments of extra-nuclear DNA formed during cell division, provide a non-specific but quantifiable marker of DNA damage. Micronuclei have been used to assess carcinogen exposure and as an intermediate endpoint in chemoprevention trials. As part of an ongoing chemoprevention trial, heavy smokers underwent screening bronchoscopy, with biopsies taken at 6 standardized sites. Micronuclei counts were obtained for each site in each of the 40 volunteers found to have squamous metaplasia. Unlike squamous metaplasia, the average micronuclei counts among these heavy smokers were not associated with smoking history. Micronuclei counts were also not associated with the presence or extent of metaplasia. A striking degree of intra-individual variability was observed by comparing the micronuclei counts from different biopsy sites within individuals. The findings suggest that use of micronuclei from single sites may be misleading as a marker of carcinogen exposure or as an estimate of cancer risk. Serial measurements in individuals may provide the most useful information concerning carcinogenic exposure and the impact of chemopreventive agents.

Adult↗
PubMed1999

Variations on an Expectancy-Value Model of Motivation in Science.

Relationships among motivational variables from goal theory and expectancy-value theory were investigated in this correlational study of high school students. Self-report surveys of motivation in science were collected during biology classes from 69 males and 80 females. Outcome measures were effort, persistence, and achievement. Gender differences were noted in the pattern of zero-order correlations. Internal motivation variables were related to achievement in males but not females. Regression analyses indicated that the motivation variables explained large proportions of variance in the outcomes. However, the contribution of individual variables differed by gender. Most notable was perceived ability, which contributed significantly to predicting outcome measures for females but not males. Findings suggest that interventions may need to focus on different motivational aspects depending on gender. Copyright 1999 Academic Press.

Journal Article↗
PubMed1993

Pharmacokinetic modeling as a tool for biological monitoring.

The relationships between biological indicators and exposure or tissue burdens are determined by the pharmacokinetic behaviour of the chemical. They can be studied by pharmacokinetic models of various types. Simple pharmacokinetic models are used here to describe general relationships valid for large groups of chemicals or situations. Important parameters to consider are the half-life of the biological indicator, the individual variability and the exposure variability. Biological sampling strategies are presented for monitoring of groups of workers, or individual workers. For specific chemicals, mainly solvents, more elaborate models can be developed, i.e., physiologically-based pharmacokinetic models including physiological, metabolic and physicochemical parameters. Such models are useful to describe the influence of confounding factors. Physiologically-based pharmacokinetic models can also be developed for metals and metalloids. Antimony is presented here as an example. In conclusion, pharmacokinetic modeling brings much information on sampling time, sample size, limit values, effect of physical workload and of individual physiological parameters.

Antimony↗
PubMed2001

Catechol-O-methyltransferase (COMT) genetic polymorphism in a Turkish population.

Catechol-O-methyltransferase (COMT) inactivates neurotransmitters, catechol hormones and drugs such as levodopa and methyldopa. A low activity allele has been demonstrated at codon 108/158 of the soluble and membrane-bound COMT, respectively, whereby a G to A transition results in a valine to methionine substitution. Ethnic and inter-individual differences in red blood cell COMT activity have been observed in the different populations studied so far. Since, no information is available on inter-individual variability of COMT genotype in Turkish population, we genotyped 217 healthy, unrelated Turkish individuals. The allelic frequencies of COMT gene in the Turkish population were found to be the same as has been observed in Caucasians, but different from Orientals.

Adult↗
PubMed1989

Pain of first-trimester abortion: a study of psychosocial and medical predictors.

Pain during first-trimester abortion by suction-curettage under local anesthesia alone was measured with the McGill Pain Questionnaire (MPQ), and verbal and visual analogue scales in 109 women. The average intensity of abortion pain ranked among moderately intense pain recorded with the MPQ. However, the pain scores had a wide range and appeared influenced by several demographic, psychosocial and medical variables. A correlation/stratified multiple regression design was used to examine the sources of individual variability in pain reports. The results indicated that over a third of the variance in pain reports could be predicted by a set of variables which included the patient's age, self-reports of pre-operative depression, anxiety, fear, low pain tolerance, social and moral concerns, and gynecological characteristics such as uterus retroversion, menstrual pain and gestational age. Pain scores were significantly higher for women who reported moderate to severe levels of pre-abortion depression and for younger patients (13-17 years); other psychosocial and gynecological features made small additional contributions to the prediction of pain scores. The implications of the results are discussed in relation to pain management strategies and underscore the special needs of each woman facing an abortion.

Abortion, Induced↗
PubMed1976

Carcinoma of the penis.

This study updates the experience at our hospital with cancer of the penis, which now includes 122 consecutive cases seen between 1940 and 1974 with 100 per cent followup. Historical, clinical, pathological, therapeutic and followup data were extracted for all cases in a digital code for transfer to computer storage. Life tables giving cumulative survival rates through 10 years with standard deviations and age corrections were calculated for each variable. The data were tabulated for publication to emphasize the prognostic significance of individual variables for the purpose of prospective research planning. The data were then evaluated regarding indications for prophylactic inguinal lymph node dissections, if any.

Computers↗
PubMed1999

Central inhibition of sexual response in the male: a theoretical perspective.

A theoretical model for central inhibition of sexual response is proposed, postulating individual variability in the propensity for such inhibition. Whereas such inhibition is typically adaptive, individuals with high propensity may be vulnerable to sexual dysfunction, and those with low propensity to high risk sexual behavior. Evidence of the existence and localization of such inhibitory mechanisms from both the animal and human literature is reviewed. Evidence of central neurotransmitters with sexual inhibitory effects is substantial, though in most cases the inhibition is not specific to sexual response or behavior. Recent studies have identified centers in the brain stem and lateral hypothalamus which appear to have specific inhibitory effects on sexual response. A variety of adaptive mechanisms involving inhibition of sexual response are considered, some involving perception of threat, others occurring more directly as consequences of previous sexual activity. These different adaptive functions may well involve different inhibitory mechanisms. This theoretical model opens a new agenda for experimental research into adaptive sexual behavior, both human and animal.

Animals↗
PubMed1997

Normal values of patellar and ankle tendon reflex latencies.

The clinical value of latency measurement of tendon reflexes in neurological patients has been reported by several authors. However, normal values are not readily comparable. In the present study, latencies and amplitudes of patellar (PTR) and ankle tendon reflexes (ATR) were measured at rest and after facilitation in 102 normal controls. A manually operated reflex hammer, tipped with electrically conductive rubber, ensured an immediate start of the sweep of the oscilloscope. Latencies showed a significant correlation with height (r = 0.70 for PTR and r = 0.72 for ATR, P < 0.0001) and to a lesser degree with age (r = 0.16 and r = 0.30, P < 0.0001). While amplitudes were highly variable, rendering them less useful for diagnostic purposes, latencies showed minimal intra-individual variability (CV 1.5 and 0.8%, respectively). Correlation of ATR-latency with the H-reflex latency of the soleus muscle was very high (r = 0.97, P < 0.0001). Comparison with three other hammer types yielded corresponding results with a hammer supplied with a piezo-electric element; however, significantly shorter latencies were found with a hammer with a microswitch, and with another hammer with a spring-contact, due to a delay from the tap on the tendon until the start of the sweep of the monitor.

Adult↗
PubMed2003

Accuracy of collateral source reports in very mild to mild dementia of the Alzheimer type.

OBJECTIVES: To examine the reporting accuracy of collateral sources (knowledgeable informants) regarding very mild and mild dementia of the Alzheimer type (DAT) and to identify characteristics associated with collateral source accuracy. DESIGN: Secondary data analysis of initial visits of individuals enrolled in a longitudinal study of healthy aging and Alzheimer disease. SETTING: Urban Alzheimer disease research center. PARTICIPANTS: Pairs of 515 individuals with very mild (n = 203) or mild (n = 312) DAT and their collateral sources. MEASUREMENTS: Collateral sources were asked separately during a semistructured interview by experienced clinicians to report current ability of the individual with DAT in memory, orientation, and judgment and problem solving. The clinical performance of the individuals with DAT in these domains was compared with these predictions. RESULTS: Collateral sources were consistently and significantly accurate in reporting the cognitive capabilities of individuals with very mild and mild DAT. Although all types of collateral sources performed significantly better than chance, individual variables that correlated with collateral source accuracy included spousal relationship; living with the individual with DAT; frequent exposure to the individual; and age, education level, sex and dementia severity of the individual with DAT. CONCLUSION: Collateral sources are accurate in reporting the cognitive capabilities of individuals with DAT, even in the very mild stage of dementia.

Aged↗
PubMed1997

Heterophil/lymphocyte ratio as a selection criterion for heat resistance in domestic fowls.

1. Two experiments were conducted to examine the Heterophil/Lymphocyte ratio (H/L) as criterion for selection for resistance to heat stress and some aspects of general resistance in domestic fowls. 2. The first experiment on a small sample (n = 64) of light breed Iraqi local fowls showed that this ratio could be used as an indicator of heat stress resistance. 3. The second experiment on a large sample (n = 1160) of heavy parent stock confirmed the results. It showed that there was a different H/L ratio for the two strains and that there was much individual variability in the H/L ratio within-strain that could be utilised for individual selection for heat resistance. 4. The H/L ratio was highly heritable; Resistant and Sensitive groups, defining all individuals with an H/L ratio over the upper 95% confidence limit as 'Sensitive' and those below as 'Resistant' produced progeny with significantly different H/L ratios. 5. There were indications of differences in mortality between the progeny of the Resistant and the Sensitive groups. 6. The H/L indicator could be used as a criterion to select for heat stress resistance.

Animals↗
PubMed2000

Do confounding or selection factors of residential wiring codes and magnetic fields distort findings of electromagnetic fields studies?

In contrast with several previous studies, our recent large case-control study found little association between childhood acute lymphoblastic leukemia (ALL) and electric-power-line wire codes. Here we examine internal evidence from our study to assess the possibility that selection bias and/or confounding may have affected the findings. We compared the relation between childhood ALL and wire codes and direct measurements of magnetic fields in subjects who participated in all phases of the study with the relation in all subjects, including those who declined to allow access inside the home. We found that the odds ratio for ALL among those living in homes with very high current configurations increased by 23% when 107 "partial participants" were excluded. We found similar, but slightly smaller, increases in the odds ratios when we performed the same comparisons using direct measurements of magnetic fields, excluding subjects who allowed only a measurement outside the front door. "Partial participants" tended to be characterized by lower socioeconomic status than subjects who participated fully, suggesting possible selection bias. We also examined the relation between a large number of potential confounding variables and both proxy and direct measurements of magnetic fields. Univariate adjustment for individual variables changed the odds ratio for ALL by less than 8%, while simultaneous adjustment for several factors reduced the estimate by a maximum of 15%. We conclude that while confounding alone is unlikely to be an important source of bias in our own and previous studies of magnetic fields, selection bias may be more of a concern, particularly in light of the generally low response rates among controls in case-control studies.

Case-Control Studies↗